#include "boxes.h"
#include <bits/stdc++.h>
#define f(x) min(L-p[x],p[x])
using namespace std;
typedef long long ll;
ll s1[10000010], s2[10000010];
long long delivery(int N, int K, int L, int p[]) {
int i, j;
K=min(N,K);
for (i=0; i<K; i++) { for (j=i; j<N-1; j+=K) s1[i]+=(ll)(p[j]+f(j)); }
for (i=N-1; i>=N-K; i--) { for (j=i; j>0; j-=K) s2[i%K]+=(ll)(L-p[j]+f(j)); }
ll ans=min(s1[(N-1)%K]+p[N-1]+f(N-1), s2[0]+L-p[0]+f(0)), s;
for (i=0; i<K; i++) {
s=s2[(i+1)%K]+p[i]+f(i);
ans=min(s, ans);
for (j=i+K; j<N; j+=K) {
s+=(ll)(p[j]+f(j));
s-=(ll)(L-p[j-K+1]+f(j-K+1));
ans=min(s,ans);
}
}
for (i=N-1; i>=N-K; i--) {
s=s1[(i+K-1)%K]+(L-p[i]+f(i));
ans=min(s, ans);
for (j=i-K; j>=0; j-=K) {
s+=(ll)(L-p[j]+f(j));
s-=(ll)(p[j+K-1]+f(j+K-1));
ans=min(s,ans);
}
}
return ans;
}
